160 AN INTRODUCTION TO -ENTOMOLOGY 



This pouch is known as the bursa copulatrix or copulatory pouch. In 

 some insects this pouch is a diverticulum of the vagina (Fig. 177,6*;); 

 in others it has a distinct external opening, there being two external 

 openings of the reproductive organs, the opening of the vagina and the 

 opening of the bursa copulatrix. 



When the bursa copulatrix has a distinct external opening there 

 may or may not be a passage from it to the vagina. In at least some 

 Orthoptera (Melanoplus) there is no connection between the two; 



when the eggs are laid they are 

 pushed past the opening of the 

 bursa copulatrix where they are 

 fertilized. 



In the Lepidoptera (Fig. 180), 

 there is a passage from the bursa 

 copulatrix to the vagina. In 

 this case the seminal fluid is 

 Fig. i8o.-Reproductive organs of the received by the bursa copulatrix 

 female of the milkweed butterfly; a, at the time of pairing, later it 

 ' &&&*u3ti P^ to the spermatheca, and 

 filaments of the ovary; v, opening from here it passes to the vagina. 



A bursa copulatrix is said to 



be wanting in Hymenoptera, Diptera, Heteroptera and Homoptera 

 except the Cicadas. 



The colleterial glands. There are one or two pairs of glands that 

 open into the vagina near its outlet (Fig. 177, eg) ; to these has been 

 applied the general term colleterial glands. Their function differs in 

 different insects; in some insects they secrete a cement for gluing the 

 eggs together, in others they produce a capsule or other covering 

 which protects the eggs. 



The spermathecal gland. In many insects there is a gland that 

 opens either into the spermatheca or near the opening of the sperma- 

 theca, this is the spermathecal gland (Fig. 177, sg). 



C. THE REPRODUCTIVE ORGANS OF THE MALE 



The reproductive organs of the male are quite similar in their more 

 general features to those of the female; but there are striking differ- 

 ences in details of form. 



The general features of the testes. As the reproductive elements 

 developed in the testes, the spermatazoa, always remain small, the 

 testes of a male are usually much smaller than the ovaries of the female 

 of the same species. 



